[1] Univ Manchester, Sch Nursing Midwifery & Social Work, Manchester M13 9PL, Lancs, England
[2] Royal Hallamshire Hosp, Pulm Vasc Unit, Sheffield S10 2JF, S Yorkshire, England
[3] PHA UK, Sheffield, S Yorkshire, England
[4] Royal Brompton & Harefield NHS Fdn Trust, Pulm Vasc Unit, London, England